Stacked wafer-level packaging devices

ABSTRACT

Stacked wafer-level packaging devices. In some embodiments, a wireless device includes a transceiver configured to generate a radio-frequency (RF) signal. The wireless device also includes a front-end module (FEM) in communication with the transceiver, the front-end module including a packaging substrate configured to receive a plurality of components, the front-end module further including a stacked assembly implemented on the packaging substrate, the stacked assembly including a first wafer-level packaging (WLP) device having a radio-frequency (RF) shield, the stacked assembly further including a second wafer-level packaging device having an RF shield, the second wafer-level packaging device positioned over the first wafer-level packaging device such that the RF shield of the second wafer-level packaging device is electrically connected to the RF shield of the first wafer-level packaging device. The wireless devices further includes an antenna in communication with the front-end module, the antenna configured to transmit the amplified radio-frequency signal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.15/204,391 filed Jul. 7, 2016, entitled “DEVICES AND METHODS RELATED TOSTACKED DUPLEXERS,” which claims priority to U.S. ProvisionalApplication No. 62/189,689 filed Jul. 7, 2015, entitled “DEVICES ANDMETHODS RELATED TO STACKED DUPLEXERS.” The disclosures of each of theabove-referenced applications are hereby expressly incorporated byreference herein in their respective entireties.

BACKGROUND Field

The present disclosure relates to multiplexers for radio-frequency (RF)applications.

Description of the Related Art

In some radio-frequency (RF) applications such as wireless applications,two or more RF signals can be multiplexed together to allow routing ofsuch signals through a common path. Combining of two RF signals istypically referred to as diplexing; combining of three RF signals istypically referred to as triplexing; and so on.

SUMMARY

In some implementations, the present disclosure relates to an assembly.The assembly includes a first wafer-level packaging (WLP) device havinga radio-frequency (RF) shield. The assembly also includes a second WLPdevice having an RF shield, the second WLP device positioned over thefirst WLP device such that the RF shield of the second WLP device iselectrically connected to the RF shield of the first WLP device.

In some embodiments, the first WLP device includes a first RF filter,and the second WLP device includes a second RF filter.

In some embodiments, each of the first and second RF filters includes agrounding contact pad, at least one input contact pad, and at least oneoutput contact pad.

In some embodiments, the RF shield of each of the first and second RFfilters includes a conformal coating of conductive material.

In some embodiments, the conformal coating of each RF filter iselectrically connected to the corresponding grounding contact pad.

In some embodiments, the second RF filter is in an inverted orientationsuch that the conformal coating of the RF second filter is in electricalcontact with the conformal coating of the first RF filter.

In some embodiments, the conformal coating of the second RF filter iselectrically connectable to an external ground node through thegrounding contact pad of the first RF filter.

In some embodiments, the first RF filter has a first lateral dimensionand the second RF filter has a second lateral dimension that is greaterthan the first lateral dimension such that each of a plurality of edgesof the second RF filter forms an overhang over a corresponding edge ofthe first RF filter.

In some embodiments, the second RF filter is in an upright orientation,and some or all of the grounding contact pad, the at least one inputcontact pad, and the at least one output contact pad are located at theoverhanging edges.

In some embodiments, the assembly further includes a plurality ofmounting structures configured to allow mounting of the second RF filterto a packaging substrate at locations that are laterally offset beyondthe corresponding edges of the first RF filter.

In some embodiments, at least some of the mounting structures isconfigured to provide one or more electrical connections between thesecond RF filter and the packaging substrate.

In some embodiments, the one or more electrical connections between thesecond RF filter and the packaging substrate includes a groundingconnection between the grounding contact pad of the second RF filter anda ground on the packaging substrate.

In some embodiments, the mounting structures include a printed circuitboard (PCB) implemented on each of two opposing sides of the first RFfilter, the PCB having a thickness selected to allow the second RFfilter to be positioned over the first RF filter.

In some embodiments, the mounting structures include a ball-grid array(BGA) implemented on each of two opposing sides of the first RF filter,the BGA dimensioned to allow the second RF filter to be positioned overthe first RF filter.

In some embodiments, the mounting structures include a ball-grid array(BGA) and a printed circuit board (PCB) implemented on each of twoopposing sides of the first RF filter, the BGA and the PCB dimensionedto allow the second RF filter to be positioned over the first RF filter.

In some embodiments, the mounting structures include an interposerstructure implemented on each of two opposing sides of the first RFfilter, the interposer structure dimensioned to allow the second RFfilter to be positioned over the first RF filter.

In some embodiments, the first RF filter is configured to providereceive (RX) filtering functionality for one or more RX frequency bands.

In some embodiments, the second RF filter is configured to providetransmit (TX) filtering functionality for one or more TX frequencybands.

In some embodiments, the first and second RF filters are configured toprovide duplexer functionality for the corresponding one or morefrequency bands.

In some embodiments, each of the first and second RF filters isconfigured to provide dual-band filtering capability.

In some embodiments, each of the first and second RF filters includes asurface acoustic wave (SAW) filter or a bulk acoustic wave (BAW) filter.

In some implementations, the present disclosure relates toradio-frequency (RF) module. The RF module includes a packagingsubstrate configured to receive a plurality of components. The RF modulealso includes a stacked assembly implemented on the packaging substrate,the stacked assembly including a first wafer-level packaging (WLP)device having a radio-frequency (RF) shield, the stacked assemblyfurther including a second WLP device having an RF shield, the secondWLP device positioned over the first WLP device such that the RF shieldof the second In some embodiments, the RF module is a front-end module(FEM).

In some embodiments, the stacked assembly is configured as a duplexer,such that the first WLP device includes a first RF filter and the secondWLP device includes a second RF filter.

In some implementations, the present disclosure relates to a wirelessdevice. The wireless device includes a transceiver configured togenerate a radio-frequency (RF) signal. The wireless device alsoincludes a front-end module (FEM) in communication with the transceiver,the FEM including a packaging substrate configured to receive aplurality of components, the FEM further including a stacked assemblyimplemented on the packaging substrate, the stacked assembly including afirst wafer-level packaging (WLP) device having a radio-frequency (RF)shield, the stacked assembly further including a second WLP devicehaving an RF shield, the second WLP device positioned over the first WLPdevice such that the RF shield of the second WLP device is electricallyconnected to the RF shield of the first WLP device. The wireless devicefurther includes an antenna in communication with the FEM, the antennaconfigured to transmit the amplified RF signal.

In some implementations, the present disclosure relates to aradio-frequency (RF) device. The RF device includes a packagingsubstrate configured to receive a plurality of components, the packagingsubstrate including a first side and a second side. The RF device alsoincludes a first wafer-level packaging (WLP) device implemented on thefirst side of the packaging substrate. The RF device further includes aball-grid array (BGA) implemented on the second side of the packagingsubstrate, the BGA defining a mounting volume on the second side of thepackaging substrate. The RF device further includes a second WLP deviceimplemented within the mounting volume.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a plurality of wafer-level packaging (WLP)devices, in accordance with some embodiments of the present disclosure.

FIG. 2 shows an example of a filter, in accordance with some embodimentsof the present disclosure.

FIG. 3 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 4 shows an example of a filter, in accordance with some embodimentsof the present disclosure.

FIG. 5 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 6 shows an example of a plurality of duplexers, in accordance withsome embodiments of the present disclosure.

FIGS. 7A-7C, show examples of a WLP device, in accordance with someembodiments of the present disclosure.

FIGS. 8A-8C show an examples WLP devices, in accordance with someembodiments of the present disclosure.

FIGS. 9A-9C show an example a stacked duplexer, in accordance with someembodiments of the present disclosure.

FIG. 10 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 11 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 12 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 13 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 14 shows an example of a duplexer, in accordance with someembodiments of the present disclosure.

FIG. 15 shows an example panel, in accordance with some embodiments ofthe present disclosure.

FIGS. 16A-16D show example plan views of a panel, in accordance withsome embodiments of the present disclosure.

FIGS. 17A-17D show example side sectional views of a panel, inaccordance with some embodiments of the present disclosure.

FIGS. 18A-18E show an example assembly, in accordance with someembodiments of the present disclosure.

FIG. 19 shows an example side view of a duplexer, in accordance withsome embodiments of the present disclosure.

FIG. 20 depicts an example front-end module (FEM), in accordance withsome embodiments of the present disclosure.

FIG. 21 depicts an example front-end module (FEM), in accordance withsome embodiments of the present disclosure.

FIG. 22 depicts an example wireless device, in accordance with someembodiments of the present disclosure.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

In radio-frequency (RF) applications, duplexers typically occupy themost or substantial amount of space in packaged modules. Tosignificantly reduce module sizes, duplexer sizes and/or volumes can bereduced. Some duplexer size reduction approaches rely on shrinkingfilter die and packaging sizes (e.g., wafer-level packaging (WLP)).However, it may not be possible achieve further size reductions usingthese approaches.

FIG. 1 depicts a device or an assembly 100 in which a plurality of WLPdevices are arranged in a stack configuration. Although various examplesare described herein in the context of two of such devices beingstacked, it will be understood that one or more features of the presentdisclosure can also be implemented in configurations having more thantwo devices.

For the purpose of description, it will be understood that the stackconfiguration of FIG. 1 can include the upper WLP (WLP 1 in FIG. 1)being in physical contact with the lower WLP (WLP 2 in FIG. 1) (e.g.,directly or through an intermediate layer). The stack configuration ofFIG. 1 can also include a configuration in which the upper WLP is notmounted on the lower WLP; accordingly, there may or may not be a gapbetween the two WLPs.

FIG. 2 shows that in some embodiments, the WLPs of FIG. 1 can be RFfilter devices implemented as a stacked device 100. Although variousexamples are described herein in the context of such filters orfilter-based devices, it will be understood that one or more features ofthe present disclosure can also be implemented with WLPs other thanfilters or filter-based devices. It will also be understood that one ormore features of the present disclosure can be implemented in stackedconfigurations having a filter device and a non-filter device.

For the purpose of description herein, it will be understood filters caninclude, for example, filtering circuits implemented on die, and filterdevices such as surface acoustic wave (SAW) filters and bulk acousticwave (BAW). It will also be understood that filters can include, and/orbe referred to interchangeably with, related devices such as duplexers.

FIG. 3 shows an example of a duplexer 100 that can be a more specificexample of the stacked device 100 of FIG. 2. In the example of FIG. 3, atransmit (TX) filter is shown to be stacked over a receive (RX) filter.As described herein, such an RX filter can be mounted on a circuit boardor a packaging substrate, and the TX filter can be mounted on the RXfilter or be positioned over the RX filter without necessarily beingmounted on the RX filter.

In the example of FIG. 3, each of the RX and TX filters can beconfigured to provide filtering functionality for one or more frequencybands. For example, the RX filter can be an RX dual mode SAW (DMS)filter configured to provide filtering functionality for two RXfrequency bands, and the TX filter can be a ladder filter configured toprovide filtering functionality for the two corresponding TX frequencybands. It will be understood that the RX filter and the TX filter do notnecessarily need to have one-to-one correspondence between theirrespective frequency bands.

In some embodiments, it can be desirable to position the RX DMS filteron the bottom or lower portion of the duplexer 100 to, for example,yield as little ground inductance as possible. TX ladder filters cantolerate ground inductance better; and can actually benefit from theground inductance to, for example, create harmonic notches. Accordingly,it can be desirable to position the TX latter filter in the example ofFIG. 3 over the RX DMS filter.

In the example of FIG. 3, the RX filter and the TX filter are generallydepicted as having similar lateral dimensions. In some embodiments, RXDMS filters are typically smaller than TX ladder filters. FIG. 4 showsan example configuration in which an upper TX ladder filter has a largerlateral dimension than that of a lower RX DMS filter. In someembodiments, such a TX ladder filter can be mounted on the smaller RXDMS filter. In some embodiments, overhangs resulting from the largerdimensioned TX ladder filter can be utilized to provide mounting and/orelectrical connection functionalities without necessarily having to relyon the RX DMS filter.

FIG. 5 shows an example of a duplexer 100 having an RX WLP device 102,and a TX WLP device 104 stacked thereon. The RX WLP device 102 isdepicted to provide dual band functionality for example RX bands B20 andB26. Similarly, the TX WLP device 104 is depicted to provide dual bandfunctionality for example TX bands B20 and B26. It will be understoodthat other bands can be implemented, including non-limiting examples offrequency bands disclosed herein.

In the example of FIG. 5, the TX WLP device 104 is shown to be invertedso that its flat upper surface mounts on the flat upper surface of theRX WLP device 102. The lower surface of the TX WLP device 104 (nowfacing upward) is shown to include a plurality of contact pads,including a contact pad for an antenna output (Ant), a ground contactpad (Gnd), and contact pads (Tx) for input of the two bands. Similarly,the lower surface of the RX WLP device 102 can include a plurality ofcontact pads, including a contact pad for an antenna input (Ant), aground contact pad (Gnd), and contact pads (Rx) for output of the twobands.

As further shown in FIG. 5, a plurality of SMT (surface-mounttechnology) devices such as inductors 106, 110, 114, 118 can be mountedon a circuit board or a packaging substrate, adjacent to the stackedduplexer 100. The example inductors are depicted as having 0201 SMT formfactors; however, it will be understood that other form factors can alsobe utilized. It will also be understood that other types of SMT devicescan also be implemented in a similar manner. Such SMT devices can beselected and configured to provide, for example, matching functionality.

In the example of FIG. 5, the contact pads of the TX WLP device 104 canbe electrically connected to respective locations by, for examplewirebonds. For example, the antenna (Ant) contact pad is shown to beconnected to the inductor 110 through a wirebond 112, and the Tx inputcontact pads are shown to be connected to their respective inductors114, 118 through wirebonds 116, 120. In another example, a wirebond 108is shown to electrically connect the inductor 106 to ground through aconductive coating which is in turn electrically connected to the groundcontact pad (Gnd). In some embodiments, such a conductive coating can beconfigured to provide, for example, shielding functionality for the TXWLP device 104. Additional details concerning such a conductive coatingare described herein.

In the example of FIG. 5, the contact pads of the RX WLP device 102 canbe utilized to mount the RX WLP device 102, and thus the duplexer 100,to a circuit board or a packaging substrate. In some embodiments, aconductive coating can be provide on the RX WLP device 102, and such aconductive coating can be configured to provide, for example, shieldingfunctionality for the RX WLP device 102, and/or a conductive pathbetween the conductive coating of the TX WLP device 104 and a groundplane of the circuit board. Additional details concerning such aconductive coating are described herein.

FIG. 6 shows an example configuration where a plurality of duplexers 100are shown to be implemented with a pluality of SMTs. Each of the twoexample duplexers 100 is shown be include a stack having a dual TX WLPdevice implemented over a dual RX WLP device in a manner similar to theexample of FIG. 5. The example duplexer 100 on the right side isdepicted as being configured to provide dual band duplexingfunctionality for example bands B20 and B26. The example duplexer 100 onthe left side is depicted as being configured to provide dual bandduplexing functionality for example bands B28A and B28B. Again, it willbe understood that other bands can be implemented, includingnon-limiting examples of frequency bands disclosed herein.

In one embodiment, the filters, duplexers, and/or WLPs described hereinmay be part of a dual-sided package. The dual sided package may be an RFpackage. The RF package may include a filter, duplexer, and/or a WLP ona first side (e.g., a top side) and may include a filter, duplexer,and/or a WLP on a second side (e.g., a bottom side). The dual-sidedpackage may also include mounting features and/or support structures onone side of the dual-sided package (e.g., the bottom side). For example,the dual-sided package may include a ball-grid array (BGA) on one sideof the dual-sided package. The mounting features and/or supportstructures may form/define a mounting volume on one side of thedual-sided package (e.g., on the bottom side). One or more filters,duplexers, and/or WLPs may be located within the mounting volume(formed/defined by the mounting features/support structures). Examplesof dual-sided packages that may be used herein (e.g., dual-sidedpackages that may include filters, duplexers, WLPs, etc.) are describedin U.S. Provisional Application No. 62/031,815, filed on Jul. 31, 2014,titled “DUAL-SIDED RADIO-FREQUENCY PACKAGE HAVING BALL GRID ARRAY,” andin U.S. patent application Ser. No. 14/815,426, filed on Jul. 31, 2015,titled “DUAL-SIDED RADIO-FREQUENCY PACKAGE HAVING BALL GRID ARRAY.” Thecontents of each of the above-referenced applications are herebyexpressly incorporated by reference herein in their entireties.

FIGS. 7A-7C show an example of how a WLP can be configured to provideshielding functionality and/or grounding-path functionality in duplexerssuch as the examples of FIGS. 5 and 6. FIGS. 8A-8C show an example ofhow such WLPs can be combined to form duplexers such as the examples ofFIGS. 5 and 6. FIGS. 9A-9C show an example of how such duplexers can bemounted on a circuit board or a packaging substrate.

Referring to FIGS. 7A-7C, a WLP device 130 can be a filter or afilter-based device such as the TX and RX duplexers of FIGS. 5 and 6.Such a WLP device can include a conductive coating 140 such as aconformally coated conductive layer. In some embodiments, such aconductive coating can cover some of all of the upper surface (FIG. 7C),some or all of the side walls (FIG. 7A), and selected portions of thelower surface (FIG. 7B). The coated upper surface 140 can beelectrically connected to the coated lower surface 140 of the WLP device130 through the coated surface 140 of the side wall(s). The coatedsurface 140 of the lower surface can be electrically connected to agrounding pad 132. The coated surface 140 of the lower surface can alsobe patterned so as to be electrically isolated from other non-groundingcontact pads such as an antenna contact pad 134 and signal input/outputcontact pads 136 a, 136 b (e.g., TX input pads or RX output pads). Suchelectrical isolation between the coated surface 140 of the lower surfaceand the contact pads 134, 136 a, 136 b can be achieved by, for example,an appropriate patterning of the coated surface 140.

A WLP device configured in the foregoing manner can allow two suchdevices to be stacked in a manner described herein in reference to FIGS.5 and 6, and have the conductive coating of each WLP device beelectrically connected to a ground plane on or within a circuit board ora packaging substrate. More particularly, the conductive coating of thelower WLP device (e.g., the RX WLP device 102 in FIGS. 5 and 6) can beelectrically connected to the ground plane through its grounding pad(Gnd in FIGS. 5 and 6, and 132 in FIG. 7B). The conductive coating ofthe upper WLP device (e.g., the TX WLP device 104 in FIGS. 5 and 6) canbe electrically connected to the ground plane through the conductivecoating of the lower WLP device (e.g., through an electrical contactbetween their two flat surfaces), and therefore through the groundingpad (Gnd in FIGS. 5 and 6, and 132 in FIG. 7B) of the lower WLP device.

FIGS. 8A-8C show an example of how two WLP devices 130 a, 130 b can bestacked so as to provide the foregoing electrical connection between theconductive coating of an upper WLP device 130 b and the ground plane.Referring to FIG. 8A, a lower WLP device 130 a can be formed orprovided. As described herein, such a lower WLP device can be, forexample, an RX WLP device. Referring to FIG. 8B, an electricallyconductive mounting layer 150 (e.g., an electrically conductiveadhesive) can be formed on the upper conductive surface of the lower WLPdevice 130 a. Referring to FIG. 8C, the upper WLP device 130 b can beinverted such that its conductive upper surface is facing downward, andsuch an upper WLP device 130 b can be mounted on the electricallyconductive mounting layer 150, so as to form a stacked duplexer 100.Accordingly, the conductive surface of the upper WLP device 130 b can beelectrically connected to the conductive surface of the lower WLP device130 a.

FIGS. 9A-9C show an example of how a stacked duplexer such as theexample stacked duplexer 100 of FIG. 8C can be mounted on a circuitboard or a packaging substrate. Referring to FIG. 9A, a circuit board160 can have a number of SMT devices 162 mounted thereon. Such SMTdevices can be, for example, inductors and/or other passive componentsdescribed herein in reference to FIGS. 5 and 6. Referring to FIG. 9B, astacked duplexer 100 can be mounted on the circuit board 160, within adesignated area between or adjacent the SMT devices 162. Referring toFIG. 9C, electrical connections (e.g., wirebonds) can be formed betweensome or all of the SMT devices 162 and contact pads and/or conductivecoating on the upward facing side of the upper WLP device of the stackedduplexer 100.

In the examples of FIGS. 7-9, the upper and lower WLP devices of thestacked duplexer 100 are depicted as having similar lateral dimensions.In such a situation, or when the upper WLP device has a smaller lateraldimension than the lower WLP device, a stacking configuration similar tothe examples of FIGS. 7-9 (in which the upper device is mounted on andsupported by the lower device) can be appropriate. However, when theupper WLP device has a larger lateral dimension than the lower WLPdevice, the overhang of the upper WLP device can allow implementation ofother stacking configurations.

FIGS. 10-14 show non-limiting examples of stacked duplexers where upperWLP devices have larger lateral dimensions than the lower WLP devices.Accordingly, stacking configurations that utilize the overhangs of theupper WLP devices can also be implemented.

In each of the examples of FIGS. 10-14, a stacked duplexer 100 is shownto include a lower WLP device 130 a mounted on a substrate 160 such as aprinted circuit board (PCB) through the lower WLP device's contact pads170. An upper WLP device 130 b is shown to be positioned above the lowerWLP device 130 a by a corresponding supporting arrangement. Electricalconnections for such an upper WLP device can be based on the supportingarrangement.

In the example of FIG. 10, the lower WLP device 130 a can be mountedwithin a deep cavity defined by, for example, a PCB. Accordingly, theportion indicated as 160 can be utilized to mount the lower WLP device130 a, and a portion indicated as 174 can be utilized to mount the upperWLP device 130 b. Such mounting of, as well as electrical connectionsfor the upper WLP device 130 b can be facilitated by contact pads 170.In some embodiments, either or both of the lower and upper WLP devices130 a, 130 b can be shielded by, for example, conformal coating ofconductive material. Grounding of such a conductive conformal coating,if any, for each WLP device can be made through its respective groundingpad.

In the example of FIG. 11, the lower WLP device 130 a can be mounted on,for example, a PCB 160. The upper WLP device 130 b can be mounted overthe lower WLP device 130 a by use of a relatively high ball grid array(BGA) 176. Such mounting of, as well as electrical connections for theupper WLP device 130 b can be facilitated by contact pads (not shown inFIG. 11) and the BGA 176. In some embodiments, either or both of thelower and upper WLP devices 130 a, 130 b can be shielded by, forexample, conformal coating of conductive material. Grounding of such aconductive conformal coating, if any, for each WLP device can be madethrough its respective grounding pad.

In the example of FIG. 12, the lower WLP device 130 a can be mounted on,for example, a PCB 160. The upper WLP device 130 b can be mounted on thelower WLP device 130 a in a manner similar to the examples of FIGS. 5and 6. Such a mounting can be facilitated by the upper WLP device 130 bbeing inverted so as to result in contact pads (not shown in FIG. 12)facing upward. Electrical connections for the upper WLP device 130 b canbe formed through, for example, wirebonds 176. In FIG. 12, suchwirebonds are shown to be formed between the upper WLP device 130 b andthe PCB 160; however, as described herein, one or more wirebonds can beformed between the upper WLP device and one or more SMT devices such asinductors. In some embodiments, either or both of the lower and upperWLP devices 130 a, 130 b can be shielded by, for example, conformalcoating of conductive material. Grounding of the conductive conformalcoating for the upper WLP device 130 b can be made through theconductive conformal coating for the lower WLP device 130 a.

FIG. 13 shows an example that can be a combination of the examples ofFIGS. 10 and 11. More particularly, the lower WLP device 130 a can bemounted within a shallow cavity defined by, for example, a PCB.Accordingly, the portion indicated as 160 can be utilized to mount thelower WLP device 130 a, and a portion indicated as 182 can be utilizedto form a BGA 180 to thereby allow mounting of the upper WLP device 130b over the lower WLP device 130 a. Such mounting of, as well aselectrical connections for the upper WLP device 130 b can be facilitatedby contact pads (not shown in FIG. 13) and the BGA 180. In someembodiments, either or both of the lower and upper WLP devices 130 a,130 b can be shielded by, for example, conformal coating of conductivematerial. Grounding of such a conductive conformal coating, if any, foreach WLP device can be made through its respective grounding pad.

FIG. 14 shows an example where the lower WLP device 130 a can be mountedon, for example, a PCB 160, and the upper WLP device 130 b can bemounted over the lower WLP device 130 a with use of an interposerstructure 186. Such mounting of, as well as electrical connections forthe upper WLP device 130 b can be facilitated by contact pads 184, theinterposer structure 186, and contact pads 188. In some embodiments,either or both of the lower and upper WLP devices 130 a, 130 b can beshielded by, for example, conformal coating of conductive material.Grounding of such a conductive conformal coating, if any, for each WLPdevice can be made through its respective grounding pad.

In the foregoing example of FIG. 14, fabrication can be achieved in asimple and cost-effective manner. Examples related to various processesthat can be implemented for such fabrication are described in referenceto FIGS. 15-18. As described herein, such processes can allow the upperWLP device to be coupled to the interposer structure without having toperform mounting operations in a recessed area. Such an assembly of theupper WLP device and the interposer structure can then be mounted overthe lower WLP device, again without having to perform mountingoperations in a recessed area.

FIG. 15 shows a panel 200 that can be utilized to fabricate an array ofassemblies of upper WLP devices and interposer structures. In someembodiments, the panel 200 can be, for example, a PCB 202 with aplurality of slots 204. As described herein, a portion of each slot canallow the corresponding upper WLP device to be position over the lowerWLP device, with the interposer structure providing some or all of theheight. Accordingly, each slot can be dimensioned sufficiently wide toallow positioning of the lower WLP device therein.

FIGS. 16A-16D show plan views of the indicated portion at various stagesof fabrication. FIGS. 17A-17D show side sectional views of the indicatedportion at the corresponding stages of FIGS. 16A-16D.

Referring to FIGS. 16A and 17A, contact pads 206 can be formed abouteach slot 204 on the first side of the PCB 202; and correspondingcontact pads 208 can be formed on the second side of the PCB 202. Eachcorresponding pair of contact pads 206, 208 can be electricallyconnected through, for example, a conductive via 210.

In the example stage of FIGS. 16A and 17A, a group of contact pads 206on the first side of the PCB 202 can become the contact pads 184 in theexample of FIG. 14. Similarly, the corresponding group of contact pads208 on the second side of the PCB 202 can become the contact pads 188 inthe example of FIG. 14.

Referring to FIGS. 16B and 17B, solder material 212 can be applied onthe contact pads 206 of the first side of the PCB 202. Such soldermaterial can be applied by, for example, solder printing.

Referring to FIGS. 16C and 17C, a plurality of upper WLP devices 130 bcan be positioned and mounted to their corresponding sets of contactpads 206 on the first side of the PCB 202. Such positioning of the upperWLP devices 130 b can be achieved by, for example, pick-and-placetechniques. Such mounting of the upper WLP devices can be achieved by,for example, a reflow technique so as to form solder joints between thecorresponding contact pads 206 on the first side of the PCB 202 andcontact pads 214 on the upper WLP devices 130 b.

Referring to FIGS. 16D and 17D, an array of upper WLP devices mounted onthe PCB 202 in the foregoing manner can be singulated so as to yield aplurality of individual assemblies 220. Such singulation can be achievedalong cut paths 216 and 218, utilizing, for example, cutting, sawing,etc. As shown in FIG. 17D, portions of the PCB 202 adjacent to the cutpaths 216 become the interposer structures for the correspondingassemblies 220.

FIGS. 18A-18E show an example of how an assembly 220 (of an upper WLPdevice and corresponding interposer structure) can be combined with alower WLP device so as to yield a stacked duplexer configuration. Suchan assembly 220 can be fabricated as described in reference to FIGS.15-17.

Referring to FIG. 18A, a packaging substrate 230 such as a PCB can beformed or provided. Although not shown in FIG. 18A, such a packagingsubstrate can include a plurality of contact pads.

Referring to FIG. 18B, a plurality of solder features can be formed onthe corresponding contact pads of the packaging substrate 230. Suchsolder features can be formed by, for example, screen printing of soldermaterial and flux. In the example of FIG. 18B, a group of solderfeatures indicated as 232 can be utilized for mounting of one or moreSMT devices. A group of solder features indicated as 234 can be utilizedfor mounting of a lower WLP device, as well as an assembly 220 (of anupper WLP device and corresponding interposer structure) described inreference to FIGS. 15-17. A group of solder features indicated as 236can be utilized for mounting of another component such as a die.

Referring to FIG. 18C, a plurality of SMT devices 238 are shown to bemounted on the packaging substrate through the solder features 232. Alower WLP device 130 a is shown to be mounted on the packaging substratethrough a portion of the solder features 234. An assembly 220 (of anupper WLP device and corresponding interposer structure), described inreference to FIGS. 15-17, is shown to be mounted on the packagingsubstrate through the remaining portion of the solder features 234. Insome embodiments, some or all of the foregoing mounting and soldering ofvarious parts on the packaging substrate can be achieved bypick-and-place operations and reflow methods.

As described herein, such mounting of the assembly 220 results in theupper WLP device to be positioned over the lower WLP device 130 a in astacked manner. FIG. 18D shows such a configuration, in which a stackedduplexer is indicated as 100.

Referring to FIG. 18E, an overmold structure 242 can be formed over thepackaging substrate so as to encapsulate some or all of the componentsmounted on the packaging substrate. In the example shown, such anovermold structure can encapsulate the stacked duplexer 100.

In the example of FIGS. 18A-18E, various stages of fabrication are shownfor a single packaged module. It will be understood that in someembodiments, some or all of the various steps in FIGS. 18A-18E can beimplemented for an array of such modules in a panel format. For example,various stages up to and including the overmold formation of FIG. 18Ecan be achieved in such a panel format. Then, the array of overmoldedmodules can be singulated into individual units such as the example unitof FIG. 18E.

As described herein, stacking of two or more WLP devices provides asignificant reduction in footprint area needed on a circuit board toimplement functionalities associated with such WLP devices. However, thestacking itself can result in the overall height of the stacked assemblybeing greater than the height of one or the WLP devices.

FIG. 19 shows a side view of a stacked duplexer 100 similar to theexample described in reference to FIGS. 14-18. In FIG. 19, the height ofthe lower WLP device is indicated as t1, and the additional heightresulting from the upper WLP device being positioned over the lower WLPdevice is indicated as t2. In some embodiments, either or both of suchheights associated with the thicknesses of the two WLP devices and theoffset between the two WLP devices can be selected so as to yield anoverall height that is within some packaging specification.

As described herein, stacking of devices such as WLP devices can resultin significant reduction in lateral area needed to implementfunctionalities associated with such devices. FIGS. 20 and 21 show howsignificant such reduction in area can be. FIG. 20 depicts an examplefront-end module (FEM) 250 configured with multi-band capability. Eightfilter devices 252 are shown to be mounted on a packaging substrate 160,among other components such as a switch die, a power amplifier (PA) die,one or more matching networks (OPM), an antenna switch module (ASM), andvarious SMT passive devices. As one can see, the area occupied by thefilter devices 252 is a significant portion of the total area availableon the packaging substrate 160.

FIG. 21 depicts a front-end module (FEM) 300 configured with multi-bandcapability, and having similar lateral dimensions as the example FEM 250of FIG. 20. Eight filter devices 252 are shown to be implemented as fourstacked filter devices 100 having one or more features as describedherein. As one can see, the area on the packaging substrate occupied bythe stacked filter devices 100 is significantly less than thecorresponding area utilized for filtering functionality in the exampleof FIG. 20.

In some implementations, a device and/or a circuit having one or morefeatures described herein can be included in an RF device such as awireless device. Such a device and/or a circuit can be implementeddirectly in the wireless device, in a modular form as described herein,or in some combination thereof. In some embodiments, such a wirelessdevice can include, for example, a cellular phone, a smart-phone, ahand-held wireless device with or without phone functionality, awireless tablet, etc.

FIG. 22 depicts an example wireless device 400 having one or moreadvantageous features described herein. In the context of a modulehaving one or more features as described herein, such a module can begenerally depicted by a dashed box 300, and can be implemented as, forexample, a front-end module (FEM).

Referring to FIG. 22, power amplifiers (PAs) 310 a-310 d can receivetheir respective RF signals from a transceiver 410 that can beconfigured and operated in known manners to generate RF signals to beamplified and transmitted, and to process received signals. Thetransceiver 410 is shown to interact with a baseband sub-system 408 thatis configured to provide conversion between data and/or voice signalssuitable for a user and RF signals suitable for the transceiver 410. Thetransceiver 410 is also shown to be connected to a power managementcomponent 406 that is configured to manage power for the operation ofthe wireless device. Such power management can also control operationsof the baseband sub-system 408 and the module 300.

The baseband sub-system 408 is shown to be connected to a user interface402 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 408 can also beconnected to a memory 404 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

In the example wireless device 400, outputs of the PAs 310 a-310 d areshown to be matched (via respective match circuits 306 a-306 d) androuted to an antenna 416 through a band selection switch 308, theirrespective duplexers 100 a-100 d and an antenna switch 414. In someembodiments, each of the duplexers 100 a-100 d can allow transmit andreceive operations to be performed simultaneously using a common antenna(e.g., 416). In FIG. 22, received signals are shown to be routed to “Rx”paths (not shown) that can include, for example, a low-noise amplifier(LNA).

In some embodiments, some or all of the duplexers 100 a-100 d can have astacked configuration as described herein.

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS.

One or more features of the present disclosure can be implemented withvarious cellular frequency bands as described herein. Examples of suchbands are listed in Table 1. It will be understood that at least some ofthe bands can be divided into sub-bands. It will also be understood thatone or more features of the present disclosure can be implemented withfrequency ranges that do not have designations such as the examples ofTable 1.

TABLE 1 Tx Frequency Rx Frequency Band Mode Range (MHz) Range (MHz) B1FDD 1,920-1,980 2,110-2,170 B2 FDD 1,850-1,910 1,930-1,990 B3 FDD1,710-1,785 1,805-1,880 B4 FDD 1,710-1,755 2,110-2,155 B5 FDD 824-849869-894 B6 FDD 830-840 875-885 B7 FDD 2,500-2,570 2,620-2,690 B8 FDD880-915 925-960 B9 FDD 1,749.9-1,784.9 1,844.9-1,879.9 B10 FDD1,710-1,770 2,110-2,170 B11 FDD 1,427.9-1,447.9 1,475.9-1,495.9 B12 FDD699-716 729-746 B13 FDD 777-787 746-756 B14 FDD 788-798 758-768 B15 FDD1,900-1,920 2,600-2,620 B16 FDD 2,010-2,025 2,585-2,600 B17 FDD 704-716734-746 B18 FDD 815-830 860-875 B19 FDD 830-845 875-890 B20 FDD 832-862791-821 B21 FDD 1,447.9-1,462.9 1,495.9-1,510.9 B22 FDD 3,410-3,4903,510-3,590 B23 FDD 2,000-2,020 2,180-2,200 B24 FDD 1,626.5-1,660.51,525-1,559 B25 FDD 1,850-1,915 1,930-1,995 B26 FDD 814-849 859-894 B27FDD 807-824 852-869 B28 FDD 703-748 758-803 B29 FDD N/A 716-728 B30 FDD2,305-2,315 2,350-2,360 B31 FDD 452.5-457.5 462.5-467.5 B32 FDD N/A1,452-1,496 B33 TDD 1,900-1,920 1,900-1,920 B34 TDD 2,010-2,0252,010-2,025 B35 TDD 1,850-1,910 1,850-1,910 B36 TDD 1,930-1,9901,930-1,990 B37 TDD 1,910-1,930 1,910-1,930 B38 TDD 2,570-2,6202,570-2,620 B39 TDD 1,880-1,920 1,880-1,920 B40 TDD 2,300-2,4002,300-2,400 B41 TDD 2,496-2,690 2,496-2,690 B42 TDD 3,400-3,6003,400-3,600 B43 TDD 3,600-3,800 3,600-3,800 B44 TDD 703-803 703-803

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Description using the singularor plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While some embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A wireless device comprising: a transceiverconfigured to generate a radio-frequency (RF) signal; a front-end module(FEM) in communication with the transceiver, the front-end moduleincluding a packaging substrate configured to receive a plurality ofcomponents, the front-end module further including a stacked assemblyimplemented on the packaging substrate, the stacked assembly including afirst wafer-level packaging (WLP) device having a radio-frequency (RF)shield, the stacked assembly further including a second wafer-levelpackaging device having an RF shield, the second wafer-level packagingdevice positioned over the first wafer-level packaging device such thatthe RF shield of the second wafer-level packaging device is electricallyconnected to the RF shield of the first wafer-level packaging device;and an antenna in communication with the front-end module, the antennaconfigured to transmit the amplified radio-frequency signal.
 2. Thewireless device of claim 1 wherein the first wafer-level packagingdevice includes a first radio-frequency filter, and the secondwafer-level packaging device includes a second radio-frequency filter.3. The wireless device of claim 2 wherein each of the first and secondradio-frequency filters includes a grounding contact pad, at least oneinput contact pad, and at least one output contact pad.
 4. The wirelessdevice of claim 3 wherein the radio-frequency shield of each of thefirst and second RF filters includes a conformal coating of conductivematerial.
 5. The wireless device of claim 4 wherein the conformalcoating of each radio-frequency filter is electrically connected to thecorresponding grounding contact pad.
 6. The wireless device of claim 5wherein the second radio-frequency filter is in an inverted orientationsuch that the conformal coating of the radio-frequency second filter isin electrical contact with the conformal coating of the firstradio-frequency filter.
 7. The wireless device of claim 6 wherein theconformal coating of the second RF filter is electrically connectable toan external ground node through the grounding contact pad of the firstradio-frequency filter.
 8. The wireless device of claim 5 wherein thefirst radio-frequency filter has a first lateral dimension and thesecond radio-frequency filter has a second lateral dimension that isgreater than the first lateral dimension such that each of a pluralityof edges of the second radio-frequency filter forms an overhang over acorresponding edge of the first radio-frequency filter.
 9. The wirelessdevice of claim 8 wherein the second radio-frequency filter is in anupright orientation, and some or all of the grounding contact pad, theat least one input contact pad, and the at least one output contact padare located at the overhanging edges.
 10. The wireless device of claim 9further comprising a plurality of mounting structures configured toallow mounting of the second radio-frequency filter to a packagingsubstrate at locations that are laterally offset beyond thecorresponding edges of the first radio-frequency filter.
 11. Thewireless device of claim 10 wherein at least some of the mountingstructures is configured to provide one or more electrical connectionsbetween the second radio-frequency filter and the packaging substrate.12. The wireless device of claim 11 wherein the one or more electricalconnections between the second radio-frequency filter and the packagingsubstrate includes a grounding connection between the grounding contactpad of the second radio-frequency filter and a ground on the packagingsubstrate.
 13. The wireless device of claim 12 wherein the mountingstructures include a printed circuit board (PCB) implemented on each oftwo opposing sides of the first radio-frequency filter, the printedcircuit board having a thickness selected to allow the secondradio-frequency filter to be positioned over the first RF filter. 14.The wireless device of claim 12 wherein the mounting structures includea ball-grid array (BGA) implemented on each of two opposing sides of thefirst radio-frequency filter, the ball-grid array dimensioned to allowthe second radio-frequency filter to be positioned over the firstradio-frequency filter.
 15. The wireless device of claim 12 wherein themounting structures include a ball-grid array (BGA) and a printedcircuit board (PCB) implemented on each of two opposing sides of thefirst RF filter, the ball-grid array and the printed circuit boarddimensioned to allow the second radio-frequency filter to be positionedover the radio-frequency filter.
 16. The wireless device of claim 12wherein the mounting structures include an interposer structureimplemented on each of two opposing sides of the first RF filter, theinterposer structure dimensioned to allow the second radio-frequencyfilter to be positioned over the first radio-frequency filter.
 17. Thewireless device of claim 2 wherein the first radio-frequency filter isconfigured to provide receive (RX) filtering functionality for one ormore receive frequency bands.
 18. The wireless device of claim 17wherein the second radio-frequency filter is configured to providetransmit (TX) filtering functionality for one or more transmit frequencybands.
 19. The wireless device of claim 18 wherein the first and secondradio-frequency filters are configured to provide duplexer functionalityfor the corresponding one or more frequency bands.
 20. A radio-frequency(RF) device comprising: a packaging substrate configured to receive aplurality of components, the packaging substrate including a first sideand a second side; a first wafer-level packaging (WLP) deviceimplemented on the first side of the packaging substrate; a ball-gridarray (BGA) implemented on the second side of the packaging substrate,the ball-grid array defining a mounting volume on the second side of thepackaging substrate; and a second wafer-level packaging deviceimplemented within the mounting volume.